I just got it! Turns out, it wasn't my Timer0 that was wrong; it was C7B after all. Long story short, I did need to use the results I got in Seed Finder that said "Initial frame 0, Target frame 32." When I found a seed that, rather than being 28/28, was 0/32, I punched in the ID I got from that and found 0/31, with the right time and keypress; I knew I was close! So I just did one ID advance and then got the ID!
Thank you very much for your help through all this!
Also, for when you get back on: Is there any impediment to Pokemon being RNG bred while N's Castle is still up? I want to breed some things and hatch them there if that's possible.